The invention relates to a wishbone of a wheel-suspension system for a motor-vehicle wheel, comprising a one-piece casting with a fixing zone for fixing to a bearing arrangement of the wheel, with further fixing zones for fixing to a chassis of the motor vehicle, and with a flat zone with at least one aperture.
In motor-vehicle construction, wishbones are used to control and steer the wheels. At one end, the wishbone makes the connection to the bearing arrangement of the wheel and, at the other end, it makes the connection to the chassis of the vehicle. In addition to the wheel bearing and the drive shaft, the bearing arrangement also includes a pivot bearing, a connection to the axle stub and to a control joint, to the track rod and further elements for the steering, driving, suspension and braking of the vehicle. During operation of the vehicle, the wishbone is subject to many different stresses. For this reason; two wishbones per wheel are often provided. The high stresses on the wishbone can be absorbed by using a particularly strong and sturdy construction. Such a construction often entails a high weight as well, and this leads to higher fuel consumption. The safety of the vehicle in the case of a collision also requires optimum design of the wishbone.
DE 38 00 944 C1 has disclosed a bearing arrangement for a one-piece wishbone of a wheel-suspension system. The wishbone itself is an intrinsically reinforced component, which is connected at the wheel end to the wheel carrier. At the other end, the wishbone is connected to a longitudinal member of the vehicle body by two bearing elements, comprising bearing studs and bearing holes, which are arranged in alignment with one another in the direction of travel. In the event of a collision in or counter to the direction of travel, one of the bearing elements, which is cantilever-mounted, is released. The impact energy is not transmitted to the passenger cell but is absorbed by deformation of the longitudinal member. The relatively rigid and heavy wishbone is also prevented from penetrating the passenger cell. After a collision, it is necessary to replace or repair at least the longitudinal member. Overall, the longitudinal member of a vehicle is significantly heavier and less easily accessible than the wishbone.
Taking this prior art as a starting point, it is the object of the invention to specify a wishbone of a wheel-suspension system by means of which the vehicle""s weight and the cost of repair is reduced while meeting higher requirements on vehicle safety and fuel consumption.
The foregoing object is achieved by a wishbone of a wheel-suspension system for a motor-vehicle wheel, comprising a one-piece casting with a fixing zone for fixing to a bearing arrangement of the wheel, with further fixing zones for fixing to a chassis of the motor vehicle, and with a flat zone with at least one aperture, the aperture being of dumbbell-shaped and/or kidney-shaped design.
It is advantageous that, if the motor vehicle is involved in an impact, the impact energy is absorbed by defined deformation of the wishbone. This is achieved by the fact that, adjacent to the kidney-shaped aperture, the flat zone of the wishbone has a ramp with a wall thickness that increases towards the kidney-shaped aperture.
It is also advantageous that, if the motor vehicle is involved in an impact, the wishbone is deformed in a defined manner without failing by breaking. This is achieved by the fact that a first dumbbell-shaped aperture is arranged between the ramp and the fixing zone for fixing to the bearing arrangement of the wheel. This is achieved by the fact that, between the ends of the dumbbell, the second dumbbell-shaped aperture has a connecting zone which tapers towards the first fixing zone for fixing to the chassis of the motor vehicle.
The apertures and the ramp ensure that there is a considerable weight saving for a comparable strength. The apertures allow dirty water to drain away more easily. The apertures can also be used as ducts for various lines.